A method for producing a ceramic object based on silver oxide, niobium oxide and tantalum oxide, hereinafter referred to as ANT, is known from printed publication WO 98/03446, in which small amounts of these oxides and, if applicable, other oxides are mixed together and prepared in the form of a calcined powder with a particle size of between 1 and 2 μm. This calcined powder is pressed and subsequently sintered at a temperature of between 1150° C. and 1250° C.
The known method for producing a ceramic object is disadvantageous in that it does not permit the production of a dense, phase-heterogeneous ceramic material in which two different components are present as separate phases. Due to the small size of the particles that are mixed together, a phase equilibrium can develop during sintering of the ceramic material, which then contains the various components of the ANT ceramic material in the form of a “solid solution”. In particular, it does not permit the production of a dense, phase-heterogeneous ceramic material in which the individual phases exhibit different compositions of ANT.
The production of a phase-heterogeneous ceramic material based on silver, niobium and tantalum would, for example, be desirable for compensation of the temperature coefficient of the relative permittivity ε of a phase A with an opposing temperature coefficient of a different phase B, which exhibits a different composition from that of phase A.